Mostro Tail Belt Noise. Need Help!!!

[Razorback Flyer]

So I pulled her off the wall and dusted her off. Thought Id take her out tomorrow. As I turn the head the tail belt is popping. Ive tried loosening, tightening, twisting the boom. the only way I can get the popping to quit is to running the belt loose. Well more loose then what the manual calls for. Do you think the belt may have a set kink of sorts from hanging idle on the wall for over 6 months, and should I just fly it, if that's the case. The Belt does ride fin side of the pulley, not centered. Any Ideas,or help would be appreciated!!

[munger]

I have 2 Mostros and both of them had the belt slap. It was mainly noticeable when hovering. I never experienced any problems but thought it was annoying. Then I saw on line that a few people with other belt drives and carbon booms were experiencing the same. The solution for them was a cardboard tube.

So I tried the same but I couldn't find a cardboard tube the right size so I used needlepoint material. I rolled it up in a tube sprayed it with spray on adhesive and inserted it inside the boom. I then used epoxy to glue down the ends to make sure it would never come loose.

It was a quiet machine before. Now it's stealth.

[Razorback Flyer]

Originally Posted by munger

I have 2 Mostros and both of them had the belt slap. It was mainly noticeable when hovering. I never experienced any problems but thought it was annoying. Then I saw on line that a few people with other belt drives and carbon booms were experiencing the same. The solution for them was a cardboard tube.

So I tried the same but I couldn't find a cardboard tube the right size so I used needlepoint material. I rolled it up in a tube sprayed it with spray on adhesive and inserted it inside the boom. I then used epoxy to glue down the ends to make sure it would never come loose.

It was a quiet machine before. Now it's stealth.

Thanks for the reply Munger. I don't notice it when I actually spool it up on the bench. Its just when im spinning it by hand. I don't remember hearing it when I flew it. I seriously hung it up and haven't flown it in 6 or more months. The noise is like a pop about every head rotation.

[munger]

Yep that is it.

I am not sure why it just started for you.

Maybe over time it loosened up?

[fatboyrob]

mine makes a clicking/popping noise when spinning the head by hand i have changed the the belt and both tensioners but it did nothing. i have no dust from a wearing belt so it carnt be doing any harm. you could always spray it with silicon spray that would stop it making any noise and will not harm the belt

[guyguerra]

I have 2 E models and do not have any belt problems. I also have a third one I just bought but haven't flown yet, but I changed the boom to a black one I painted and it seems fine. I also have two friends that have 2 E models each and I haven't heard of it with thiers. Have you pulled the boom off and verified that there's no twist in the belt?

[Alex M K]

Mine makes no noise when I rotate by hand.

But, then I go fly and after I land, on spooling down, once the motor stops puling, I can hear a clack clack clack noise. It doesn't get any worse if I am close or far. I guess something heats up and causes it, then cools down and all is fine

It never bothered me, or caused any concerns...I just fly it and that's it. Does that all the time.

kind regards

Alex

[Razorback Flyer]

So, I only got 2 flights in today on the Mostro, but both flights, I had no issues. Upon spool down, I could barely hear a click, but so lite. Had no vibes, and it flew awesome. I see why You all love this heli so much. Its probably the first flight since Ive put on this Heli since Before IRCHA. Im not the best pilot and a tad intimidated by the 700 size, and all the BS going down with this brand. I couldn't stand something happening and not getting parts. I got a total of 18 flights on this thing. And I could not just sell it for so cheap. Almost decided to pull everything out of it and hang her in the game room. All that being said, after almost 9 months of looking at her on the wall, and 9 more months of flying my other 700's. I loved the way it flew today, even if it was only twice.
So back to the popping or clicking, now that Im home I just rotated the head by hand and the popping is loud again. Ugh! I have not taken the boom totally off to see if the belt has a twist. There is no belt wear. Last night I only loosened and tightened the belt tension. I just don't remember this noise right after the build.

[fatboyrob]

dont worry about it mine has had loads of flights and always makes this noise when i spin the head i carnt hear anything under load though

[guyguerra]

I flew a Logo 690 for about 30 flights and finally flew with a friend with a 600. His was perfectly quiet and would spin easily compared to mine. I pulled the boom and sure enough I had twisted it in the build. I also twisted a Mostro but caught it at the bench check. It's easy enough to do. Its one of the first things to look at if a belt makes a noise or spins tight. It won't show wear but it will have more resistance. If a belt makes a noise you should find out what is causing it before you end up with a wreck. It's not normal.
I hate when people recommend extra work that wastes time due to some extremely rare thing. This one is an easy check. Just loosen the two clamp bolts on the mono block, pull the belt off the front tail gear, slide the boom out and use a flash light to look in the boom. Just don't accidentally twist the belt before you can see it so you know if this was the problem. You'll know if you fix it as it should free spin like a dream. Should take about 15 minutes to pull it and put it back on. Mostro booms come off very easy. You won't need to touch the tail area.

[Razorback Flyer]

Originally Posted by guyguerra

I flew a Logo 690 for about 30 flights and finally flew with a friend with a 600. His was perfectly quiet and would spin easily compared to mine. I pulled the boom and sure enough I had twisted it in the build. I also twisted a Mostro but caught it at the bench check. It's easy enough to do. Its one of the first things to look at if a belt makes a noise or spins tight. It won't show wear but it will have more resistance. If a belt makes a noise you should find out what is causing it before you end up with a wreck. It's not normal.
I hate when people recommend extra work that wastes time due to some extremely rare thing. This one is an easy check. Just loosen the two clamp bolts on the mono block, pull the belt off the front tail gear, slide the boom out and use a flash light to look in the boom. Just don't accidentally twist the belt before you can see it so you know if this was the problem. You'll know if you fix it as it should free spin like a dream. Should take about 15 minutes to pull it and put it back on. Mostro booms come off very easy. You won't need to touch the tail area.

Thanks guy, I will do this, because now that u say it, it does have some resistance when rotating. I will update after Easter. Thanks for all the input and help!

[guyguerra]

Good luck with it. If that's not it at least you won't be out much time and you might stumble on something else. There's something in there causing it and it can't be many things on a Mostro 😀

[tony stevens]

You don't need to pull the boom, just look down through the tail box,

[Technoman]

Gotta chime in here. The clicking has nothing to do with the belt . The pinned tailcase gear wears and starts to walk and "click". Mine started at 30 flights. Tom the team pilot and I went through this way back when. Before it wears too far you want to use red Loctite to take up the slop. Mine never made noise again. Never heard about the cardboard fix like in my Diabolo. My hearing doesn't pick it up. Belts don't "click" and you really don't want to ignore it or screw around with belt tension to mask it.
Cheers,Scott

[Razorback Flyer]

Originally Posted by Technoman

Gotta chime in here. The clicking has nothing to do with the belt . The pinned tailcase gear wears and starts to walk and "click". Mine started at 30 flights. Tom the team pilot and I went through this way back when. Before it wears too far you want to use red Loctite to take up the slop. Mine never made noise again. Never heard about the cardboard fix like in my Diabolo. My hearing doesn't pick it up. Belts don't "click" and you really don't want to ignore it or screw around with belt tension to mask it.
Cheers,Scott

Scott, I'm confused, what exactly am I red Locktiting? I checked the set screw that is up against the pin and it is tight.

[Technoman]

Check out the manual. There is a wear factor between the 2mm x 12mm pin and the hole it sits in in the tail pulley. I caught the problem early and used red to lock it in. Green was a choice but we figured it might be real hard to take apart if needed. It's easy to detect the slop when you inspect it. The point is to keep it from moving around anymore.
Cheers

[gunny_jeeves]

Can you guys post a pic?

Mine is fine right now, but I have no spare parts for the tail. I want to see and fix this early.

[helibadger]

red threadlock on 2x12mm pin?

[gunny_jeeves]

Thanks!

[Technoman]

When mine started clicking I took it apart and could feel the slop between the pulley and shaft/pin. I flooded the whole thing with red Loctite and let it dry. After 100 more flights the red seems to have hung in there. The next step is a version of the green Loctite which comes in different forms as a bearing "retainer". Problem is the green takes a lot more heat to remove if needed. Thanks for the diagram badger...